Impacts of XBT, TAO, Altimetry and ARGO Observations on the Tropical Pacific Ocean Data Assimilation

This study aims at assessing the relative impacts of four major components of the tropical Pacific Ocean observing system on assimilation of temperature and salinity fields. Observations were collected over a period between January 2001 through June 2003 including temperature data from the expendable bathythermographs （XBT）, thermistor data from the Tropical Ocean Global Atmosphere Tropical Atmosphere-Ocean （TOGA-TAO） mooring array, sea level anomalies from the Topex/Poseidon and Jason-1 altimetry （T/P-J）, and temperature and salinity profiles from the Array for Real-time Geostrophic Oceanography （ARGO） floats. An efficient three-dimensional variational analysis-based method was introduced to assimilate the above data into the tropical-Pacific circulation model. To evaluate the impact of the individual component of the observing system, four observation system experiments were carried out. The experiment that assimilated all four components of the observing system was taken as the reference. The other three experiments were implemented by withholding one of the four components. Results show that the spatial distribution of the data influences its relative contribution. XBT observations produce the most distinguished effects on temperature analyses in the off-equatorial region due to the large amount of measurements and high quality. Similarly, the impact of TAO is dominant in the equatorial region due to the focus of the spatial distribution. The Topex/Poseidon-Jason-1 can be highly complementary where the XBT and TAO observations are sparse. The contribution of XBT or TAO on the assimilated salinity is made by the model dynamics because no salinity observations from them are assimilated. Therefore, T/P-J, as a main source for providing salinity data, has been shown to have greater impacts than either XBT or TAO on the salinity analysis. Although ARGO includes the subsurface observations, the relatively smaller number of observation makes it have the smallest contribution to the assimilation syst     

分形插值参数的遗传优化及其ARGO海温场应用试验

针对常规分形插值方法中垂直压缩因子参数无公认选择标准和有效途径的问题,提出一种分形插值的改进算法,用遗传算法对分形插值模型的垂直压缩参数进行了优化选择并进行了ARGO海温资料插值加密的对比试验。试验结果表明,经遗传优化后的分形插值方法在海温复杂细节结构和小尺度特征描述等方面较常规插值等方法更具优势,改进了分形插值结果的客观性和正确性。     

Mixed Layer Depth and its Variability in the Eastern Equatorial Indian Ocean as Revealed by Observations and Model Simulations

Mixed layer depth (MLD) variability in the Eastern Equatorial Indian Ocean (EEIO) from a hindcast run of an Ocean General Circulation Model (OGCM) forced by daily winds and radiative fluxes from NCEP-NCAR reanalysis from 2004 to 2006 is investigated. Model MLD compares well with the ～20,000 observations from Argo floats and a TRITON buoy (1.5°S and 90°E) in the Indian Ocean. Tests with a one-dimensional upper ocean model were conducted to assess the impact on the MLD simulations that would result from the lack of the diurnal cycle in the forcing applied to the OGCM. The error was of the order of ～12 m. MLD at the TRITON buoy location shows a bimodal pattern with deep MLD during May–June and December–January. MLD pattern during fall 2006 was significantly different from the climatology and was rather shallow during December–January both in the model and observation. An examination of mixed layer heat and salt budget suggested salinity freshening caused by the advective and vertical diffusive mixing to be the cause of shallow MLD.     

Long-term and real-time monitoring system of the East/Japan sea

Long-term, continuous, and real-time ocean monitoring has been undertaken in order to evaluate various oceanographic phenomena and processes in the East/Japan Sea. Recent technical advances combined with our concerted efforts have allowed us to establish a real-time monitoring system and to accumulate considerable knowledge on what has been taking place in water properties, current systems, and circulation in the East Sea. We have obtained information on volume transport across the Korea Strait through cable voltage measurements and continuous temperature and salinity profile data from ARGO floats placed throughout entire East Sea since 1997. These ARGO float data have been utilized to estimate deep current, inertial kinetic energy, and changes in water mass, especially in the northern East Sea. We have also developed the East Sea Real-time Ocean Buoy (ESROB) in coastal regions and made continual improvements till it has evolved into the most up-to-date and effective monitoring system as a result of remarkable technical progress in data communication systems. Atmospheric and oceanic measurements by ESROB have contributed to the recognition of coastal wind variability, current fluctuations, and internal waves near and off the eastern coast of Korea. Long-term current meter moorings have been in operation since 1996 between Ulleungdo and Dokdo to monitor the interbasin deep water exchanges between the Japanese and Ulleung Basins. In addition, remotely sensed satellite data could facilitate the investigation of atmospheric and oceanic surface conditions such as sea surface temperature (SST), sea surface height, near-surface winds, oceanic color, surface roughness, and so on. These satellite data revealed surface frontal structures with a fairly good spatial resolution, seasonal cycle of SST, atmospheric wind forcing, geostrophic current anomalies, and biogeochemical processes associated with physical forcing and processes. Since the East Sea has been recognized as a natural laboratory for global oceanic changes and a clue to abrupt climate change, we aim at constructing a 4-D continuous real-time monitoring system, over a decade at least, using the most advanced techniques to understand a variety of oceanic processes in the East Sea.     

发展剖面探测浮标技术,支持我国参与ARGO计划

本文介绍了国际ARGO计划的背景和科学意义，分析了ARGO计划对我国的正负面影响和我们应采取的对策，分析了ARGO计划使用的自持式剖面循环探测浮标的技术要求和关键技术，介绍了国外已有的几种自持式剖面浮标和国内正在研制的自持式剖面浮标。     

我国的海洋剖面探测浮标-COPEX

文章概述了国外Argo浮标的特点及今后的发展状况，重点详细介绍了我国自行研制的COPEX浮标的工作原理、结构设计、通讯、电路原理以及海上实验的情况。通过照片、图表绘出了该仪器的实验数据和实验结果。     

卫星遥感SSH数据在水下温度垂直分布反演中的应用研究

结合MODAS基本原理,应用动态气候态的数据同化概念,阐述应用卫星遥感SSH数据反演水下温度垂直分布的理论和方法,并利用西太平洋海区的ARGO数据进行试验,建立了单点的温度剖面,通过引入SSH数据进行水温反演,演示结果显示了卫星遥感SSH资料同化的有效性,并得出分析结论。     

Monthly Variability of Mixed Layer over Arabian Sea Using ARGO Data

The mixed layer depths over the Arabian Sea were computed for the three successive years 2004-2006 using ARGO floats data. The large availability of ARGO floats for the above period resulted in better estimation of mixed layer depth (MLD) over the Arabian Sea. The results were compared with World Ocean Atlas 1994 MLD Climatology. Marked variability in MLD on a monthly time scale is observed and it was in accordance with the wind stress and/or net heat gain variability, which are the principal factors influencing mixed layer over Arabian Sea. With the availability of large number of ARGO profile data, an attempt is made to study the monthly variability of Mixed Layer.     

基于ARGO资料的MTSAT海温产品误差分析

利用全球海洋观测网计划ARGO浮标的表层海温测量值分析了MTSAT卫星的海温反演误差。结果显示,平均绝对误差为0.73℃,均方根误差为0.885℃,满足应用需要;海温反演异常点多分布在30°N以北的高纬区域。为了确保海温产品数据的可靠性,需要通过数据误差控制技术来检测和控制海表温度反演的异常值,影像边缘和高纬地区的区域数据应谨慎使用。     

基于北斗系统的ARGO浮标设计

为了设计一种基于我国自主卫星导航定位系统的ARGO浮标,提出了应用北斗卫星导航定位系统的ARGO浮标设计方案.阐述了ARGO浮标的基本原理、应用概况和现有北斗卫星导航定位系统的基本应用,初步提出了基于北斗卫星导航系统的ARGO浮标设计方案;从通信方式、体制和定位、配重等方面对基于北斗的ARGO浮标设计进行了可行性分析,研究了基于北斗卫星导航定位系统的ARGO浮标通信方式和两种通信模式.研究表明,基于北斗卫星导航定位系统的ARGO浮标方案可行.